c150L

I'd guess a sheetmetal/self tapper was used. The washer is actually doing the sealing, but if hole was not too large, the screw itself will seal like a charm. Better yet, the screww is doing the sealing and the washer is there just for good measures.

I too was thinking the general tune up things first. Also, I believe a worn out or disconnected O2 sensor would cause an engine to run rich, use more gas. My 88 wagon went from 27.5 avg mpg all the way doen to the mid teens before I noticed that the fuel ppump had rusted out and was pumping half my gas on the road as I was driving. Was noticed dripping while idling in a parking lot. (Smaller, but getting bigger wet spot on ground in front of RR wheel.) Tried some fixes on the engine and milage continued getting worse. Engine was still working on 27 mpg, but the gas applied directly to the pavement did nothing toward improving gas milage.

My 88 wagon did same and smelled same. I couldn't find the leak. Couple weeks later, I noticed that the fuel pump had rusted out and it leaked when running. Replaced FP, milage instantly went back to 27.5 mpg average.

The clutch in my 89 XT6 has not been 100% and slips at times under very heavy loads. Been that way since I got it going on 4 years ago now. I guess if I chose to replace it, I'll probably just head in to Bumbper to Bumper and get what ever they have. Probably not the best choice, but...

Yup. Did that to get aa XT4 my boy bought.home. It didn't have a compressor in it at the time. Not a very relyable means of transportation though. If there is a slow leak, would be pulling into stations constantly to refresh a shock. If one is going to have air ride, it should work properly.

Does not appear to be a dash height switch in the diagram I linked to. Also do not see the test plug. I'll send my scans of the wiring diagrams along. (It's for an XT, but would expect to be quite similar.

You would only need to pull off one line, compresor side, then you could test fire each solenoid fron the test plug with a fused ground wire. (Carefull.) If you hold each solenoid open long enough, your car will go to the ground. Will need to think if you want that. If the compressor is working, it SHOULD come back up. In these cold months, I have had to put a jack under the left rear corner and help that one up a ways. Also, the fronts are harder/take longer to get off bottom when their totally flat. I have used a jack to assist the fronts to start their way up too. Can not go to far up with the jack or the shock will tell the ECU it's high and stop charging the strut with air. (Then either wants to open the solenoid to lower or close it to stop filling it if the height is correct.) On the XT6 US models, the wire for height does not go to the dash. Only to the test plug. That's why I tapped in there. I don't believe the models that have the dash switch have this wire in the test plug. I have a CN and US wiring diagram for XT6. Not sure what one I pointed u to online. PM me an email addy and I'll sent you the PDFs. Their actually pretty good for helping understand what this system is about. Think is states that 88 and later (except XT models) have an onboard diagnostic you can triiger from the ECU. But then your height switch would have to be working.

Here's some wiring diagrams. I have found the PDF troubleshooting files too. Some wiring diagrams

Any sort of wiring diagram would be very helpful for you. For relays, As I remember it, there is only the one behind the left front strut tower. This is the relay for the compressor only. Besides that, there's six solenoids and all have the + wire that's always hot and the - terminal is switched on and off direct from the ECU under the seat. I don't remember if the pressure switch in the air reserve tank directly triggers the compresser relay when pressure drops or if this pressure switch signals into the ECU and the ECU in turn triggers the compressor relay. There is one solenoid on each rear strut and one solenoid mounted near the front struts. One solenoid on the reserve tank and then what seems to be a somewhat troublesome solenoid in the compressor itself. That's the discharge solenoid. I had a couple of these burn out and or freeze up from moisture. Strange things happen when the system can not discharge air from any strut(s) that are higher than they are supposed to be. When you mentioned the car sitting there skewed, I thought you may have had at least one strut that was too high and the air was not discharging. That could be due to the struts solenoid, but more likely the discharge solenoid in the compressor isn't. My XT6 did this and the rears dropped. (Due to some leaking in the rear, but more due to nothing going into the rears because the fronts were too high and could not discharge. In a pinch, I have popped off one line from a front strut solenoid (compressor side, not strut side). Once the high strut is brought below the high point, the compressor should kick in to charge more air into the low struts. A high condition takes preference in the ECU over a low condition. If all low, the rears take pref over the fronts. not sure, but I think if all high the fronts take pref over the rears. (Don't quote me on that.) I have not noticed any preference between lefts and rights. But rear solenoids open at same time if low and when it comes to fronts, both will open if low and the rears are in place already. If you are to try manually energizing the solenoids, make sure you only ground (-) the switched - wire. DO NOT hit that wire with a + jumper. Also, do not ground out the + (always hot) wire going into the solenoid. Will burn your fingers and/or blow out a fuse. Hitting a + on the _ switched wire will most likely take out a transistor in the ECU. (Did that on the discharge solenoid in my XT6 and had to replace a transistor.) For the height switch on the dash, the US model XT6s did not have this provision. To get the height select on my XT6, I tapped off the height trigger wire that terminates at the test plug by the compressor relay. To toggle the height from normal to high, I have to hit that trigger once with a + wire. (Momentary contact) If I use a maintained contact switch, the thing toggles from normal to high each time I turn the ign switch off then back on. (I'm using an ingition switched wire. Someone had told me that the the dash switches are maintained contacts. I can not deny that, but also can not explain it. Perhaps it's an always hot wire feeding it, but just removing the hot fropm my XT6 does not toggle from norm to high or vise versa. I have to toggle the hot wire again to chage states. PM me if interested, I may have a PDF file someone sent me for trouble shooting the air ride. I'll look for it.

Could also be that the spider gears, which are the diff gears, have blown out in either the front or rear diff. This maty have made a noise when it went out, but possibly quite once the pieces come to rest out of the way somewhere. Something was mentioned about going to get the car. If this is a new purchase or acquire, perhaps someone broke one of the half shafts at a wheel and removed the rest of it from the spline shaft off the front or rear diff. Had to do that in an emergency with a wagon I had once just to get car home. Twas a rear wheel drive GL for a few weeks.

Be carefull adding manually operated switches to the system. The ECU switches the - leg to the solenoids and the + (most of them?) are always hot. I think sending a hot sig back into my ECU burned out the output transistor while troubleshooting my new AS XT-6 3 years ago. (Replaced that transistor and ECU has been flawless. Now if the cold weather would pass. My compressor, disch solenoid or one shock solenoid does not like the cold.)

Don't let anyone fool you. The technology required to make an internal combustion engine get milage that most can not, will not, and/or refuse to comprehend or consider has been around as long as the internal combustion itself. The more technical gizmos the auto mfg put under your dash and hood, the harder it is to do something about imporving the milage your vehicle will get. If your Sube has a carb (not electronic crap) there is much one can do and people have done to get better milage. Take the so called SUPERCARBS. Call the oil co's or auto mfg and ask them why they do not put them on our cars. If they'd even talk to you, they would tell you that the technology does not work. If so, why do they own all those patents to all those high milage carburation devices? 40 mpg should not be that far fetched for a carbed Sube. My 71 Roadrunner got the mid 20's for one summer in the early 80's. That's no light car and I'm sure the sticker for a 383 equippped vehical back then was not near 20mpg. Never saw a sticker on one of them, so don't know what it should have got. I had it as low as 4 mpg with the 440 six pack in it though.

Just another possibility, your increase in mpg may be due to the fuel level in the float bowl being lower than specified. Thus, the main jet circuit has less fuel (level in the bowl) to draw from. Back in early 80s, I put a device I made on the carb of my 72 Charger w/318 V8. The idea was, that I used a certain amount of manifold vacuum to apply a slight vacuum (lower atmospheric pressue) in the float bowl. By doing this, at cruise and normal manifold vacuum, the carb was not able to pull as much gas from the bowl and out the main jets. When one tromped on the pedal, the manufold vacuum drops, thus, the mains could pull the gas from the float as normal. Esentially, leaned the engine a bit, once up to speed and normal manifold vacuum was restored. I was getting somewhere in the mid 20s for mpg. Depending on how much I wanted to lean the engine at cruise. Acceleration was normal. Boy, I miss the carbed engines. Why were they taken away from us?

I noticed that wobble on the stub shaft, out of the front diff on a couple Subes I put half shafts in. With fingers crossed, I thought that may be normal. (Not that I knew if it was or not. Just wishfull thinking.) Anyway, never had a front diff go out. (Whether due to that wobble or not.) I know, that doesn't answer your question. Just a past experience(s) of mine. I may not check back in on this post, as perhaps I don't want to know.

Make sure to use proper lube in the LSD. (Not sure what that would be.) DO NOT put 2 different size tires on the rear of your car. Burned out 2 LSDs many moons ago with same set of mismatched rear tires. (67 Cougar GT and 71 Road Runner. (Burning lots cherrios took out the 3rd LSD in the Roadrunner. Kids those days!)

My 89 XT-6 does same thing. Last week, when really cold out, I drove home, 5 mi drive W/O touching the gas. Was idling about 2.8-3 grand. Donr that 3 years now, just when cold. Have not got to the bottom of it yet.

Have not read all relies here, but here's my quick 2 pennies. Try and get it back up on air. Mine has been there since I bought it >3 years ago. Put in 2 used front struts. One from Mike in CO for hundred bux, second from NY for $125. If putting in used, ask about visible cracks in the bag. I'd avoid such unless really cheap. I recd one used one from Hal. It had weather cracks in bag. They were OK on my wanting to return. At the time, they didn't have another avail, so they refunded me and I found next one in NY. May or may not be your rear struts, could be compressor. I revieve one in my car till I loaned it to my boy for his XT. Then found a couple used ones for reasonable. I have some troubleshooting/repair files. I'll get to you soon. PM me an email addy so I can send. (Think they are less than 1mb total. Someone here sent them to me.) Also have some text files I put together. I, for one, am glad I did not do a conversion. I think my air ride will outlast the car. (If I can help it anyway.) I hear all sorts of comments like jacked up like monkey h*&^% a foot ball and such after some conversion attempts. Last summer I saw one XT-6, probably a conversion, that appeared as it it would tip over frontward if the guy hit the brakes.

Mis matched tires on 4wd can deffinately heat up a driver train and give odd symptons. This is not a Sube deal, but a Chev Blaser or pick up deal. Last winter, I went out to a friends house and he had one of his freinds Chevs in the garage, jacked up. The front diff was baking, oil spewing out of the seals (if there is seals there) by the U joints at the hub/spindle area. They were sure that the front axle was toast and needed to be replaced. In talking about it to the driver, it was his freinds truck, found out they had a flat on way back from up north and put on a puney spare. Continued to driver 150 miles to home, in 4wd, where they found the hot diff and oil baking out the ends. Told them to change the oil and get the correct tire back on and see how it goes. Just saw them a week ago, said they never changed axles in that thing. May or may not be the tire size thing, but the bound up, non releasing 4wd lever leads me to beleive tire mismatch. Pull your car into the drive, 4wd on and unable to release from 4wd. (Dont break it trying!) Jack one wheel off the ground. (May well see that one tire rotate itself when it comes off the ground.) Maybe rock a tire back and forth a bit, and try to take out of 4wd again. What sizes are all 4 tires? What condition is each of the 4 as compared to the others. If not nearly exact in diameter on all 4, the drive train WILL bind. (Especially on reasonable traction surfaces and only when 4wd. )

I agree with the mismatched tires and tranfer case bind, but must add that everything in the drive trane after the transmission gears will be bound. Not just the transfer case. Front and rear diff, all CV and DO joints, U joints, bearings, etc. (Harder on some parts, but excess pressures on all.

Well? (I was not trying to hijack this discussion by interjecting bad info based on the actions and possible remedies I've been thinking about using on my new style FI system that my XT-6 has.) So when/where is the split between the older FI systems that the RX has VS the newer FI systems with the hot wire system. (I shall try and ref next time someone asks questions about one.) My 88 GL was SPFI and I'm nearly positive that one was also of the hot wire variety. The only FI systems I've come across on Subes has had a MAF of the hot wire variety, guess that's why I stated "Didn't know the MAF was a vane type". Guess I could have stated that I was not aware of any vane type systems in Subes. (Gives me one more thing to look at at the auction when I pop the hoods on all the Subes that go by.) In the case of a vane type MAF, would I be safe to assume that it too may have a potentiometer that may short or fault in the mid range and send wong info to the ECU? Possibly cause same sort of problems that a bad TPS sensor may?

Addiction= What I am doing right now!. It's really the only one I have. LOL

My 89 XT-6 (not a turbo) does exactly the same thing. Hesitations, stumbles, surges. Mash the throttle all the way down, seconds later, you can feel all 6 digging in. Going to change plugs first, probably wires, cap and rotor. Just seems like the plugs are fouling when it's doing that. Didn't know the MAF was a vane type. Thought it was of the heated wire variety. Will try the cleaning thing on the XT-6. What about a bad TPS. (Throttle position sensor) Between idle and wide open throttle position, isn't it a variable resistor that signals the throttle position to the ECU? If the resistance in the mid throttle position is high or low, may cause the injectorss to open or close more and send the fue/air mixture way out of whack. On all Subes I have dealt with (<1990), if the check engine light comes on and codes point to the EGR, the EGR solenoids electrical circuit is open. Found one that the plug was off the solenoid, 2 that the coil with in the solenoid was broke/burned out. An open electrical circuit is all the puter can detect. Perhas some have an EGR position sensor that the puter gets info from, but I have not seem one in a Sube yet.

There is also a thermal overload breaker built into the compressor motor. I ran into 2 of them that appearently the compressor had run too much and burned out (expired) this internal safety. One comperssor, I opened up and bypassed that thing, cleaned brushes and comm. I know, probably not the best thing to do, but I got another year out of that compressor untill I loaned it to someone else. (My car was down needing a drive shaft.) The air supspension is coool, but can take some $$$, patience, and/or electro-mechanical abilities to keep going. I'm in hopes my air ride outlasts my XT-6. Iv've been on air for 3 years now and will miss it when gone.

Awsome info! I would have thought there would have been 1:1 in there somewhere.

Yup. The transmissions I've tore apart, the final gear was not actually a gear, the splined slider in the transmissions just locked the input shaft directly tothe output shafts. Direct drive in that last gear. Where would one find the individual gear ratios in the different transmissions in our Subes. Appears to me, the front and rear differential ratios may or may not the whole kabootle when one is deciding on which drive line components to use when modding and/or converting their stock set up.